1. Field of the Invention
This invention relates to wraps for internal organs and methods for implanting such devices on a patient""s affected region through an incision in the patient""s thoracic region, and more particularly to cardiac wraps and methods for implanting such wraps.
2. Background Information
Ventricular dilation is clinically dangerous condition in which a ventricle of the patient""s heart enlarges in radius (e.g. dilates) until it is incapable of adequately pumping necessary blood through the patient""s body. A number of invasive procedures have been employed through the years in an effort to remedy ventricular dilation and other progressive diseases that bring about a weakened heart. Many of these procedures involve the use of cardiac treatment devices that are implanted through the wall of the heart, and thereby come into direct contact with the bloodstream and internal vascular tissue. One potential downside to such internally implanted devices is that continuing risk of clotting or thrombosis around the device, and possible thromboembolism. This risk is present whenever artificial materials are used, causing the accretion thereon of blood components. These risks are typically controlled, or at least reduced through the application of ongoing anticoagulant therapy. Such anticoagulants have several undesirable side effects, however.
Improved therapies and associated devices now exist that, for certain conditions, alleviate the need for internally implanted devices that directly contact the bloodstream. Ventricular dilation is a condition that can be effectively treated using implants that are essentially free of contact with the heart""s internal, blood-contacting surfaces. U.S. Pat. No. 5,800,528, entitled PASSIVE GIRDLE FOR HEART VENTRICLE FOR THERAPEUTIC AID TO PATIENTS HAVING VENTRICULAR DILATION by Lederman et al., expressly incorporated herein by reference, teaches one such treatment device. The exemplary device defines a cup-like girdle that is passed through an enlarged incision in the chest cavity and onto the ventricular region of the heart, remote from the major blood vessels. The device is passed over the affected ventricle or both affected ventricles by the clinician/surgeon using clamps for gripping the device, moving the device until it is properly seated on the ventricle. Once seated, it is held in place by small internal hooks (microhooks) or other fastening devices (sutures) that engage the outer wall of the heart. The girdle can be further constricted to compress the dilated ventricle using various mechanical systems such as pneumatic/hydraulic balloons or drawstrings. In this manner, the compression of the girdle passively (and continuously) counteracts excessive dilation of the ventricle.
U.S. Pat. No. 5,713,954, entitled EXTRA CARDIAC VENTRICULAR ASSIST DEVICE by Rosenberg et al., also expressly incorporated herein by reference, teaches an active device that dynamically assists in the actual pumping of blood by the ventricle. This device is, like the girdle, applied through an enlarged incision in the thoracic region, and secured to the ventricle. A hydraulic or pneumatic control system enables internal balloons within the device to repetitively inflate and deflate, respectively constricting and expanding the ventricle.
Both the above-described exemplary devices each employ an element termed a xe2x80x9cwrapxe2x80x9d that essentially wraps around the ventricular region of the heart. The implantation of the wrap typically requires a fairly large incision in the chest cavity, and a significant degree of manipulation by the surgeon, often using both hands and with the assistance of various clamps and the like.
As the implantation of the above-described devices often entails the use of various mechanical tools for grasping and handling the device with respect to the heart the surgeon""s tactile feedback in applying the device is reduced and, hence, his or her control over the implantation is reduced. However, it is crucial for maximum therapeutic effect that the device be properly fitted to the specific conforms of the heart and placed xe2x80x9chighxe2x80x9d enough of the ventricle (e.g. toward the major blood vessels) so that the device applies compression to the upper part of the ventricle where it is needed most. With less tactile feedback on the shape of the heart and relative location of the device, it is more difficult to ensure proper implantation, and take more procedure time to perform the implantation.
Accordingly, it is an object of this invention to provide a system and method for applying wrap that enables easier manipulation onto, and fixation to, the affected region of a patient""s heart. The wrap should be easily manipulable by one hand and arranged to enable accurate implantation onto the affected region with reduced effort. A smaller incision between the patient""s ribs (e.g. a thoracotomy), should be possible using this system and method. The system and method of this invention should generally provide the surgeon with greater control and tactile feedback during the procedure, thus enabling a quicker and more-effective placement of the device.
This invention overcomes the disadvantages of the prior art by providing a system and method for implanting a wrap on a patient""s heart, or other organ, that enables the clinician/surgeon to manipulate and apply the wrap to the affected with a single hand, maintaining the wrap in positive engagement with this treatment hand until detachment of the hand from the wrap is desired. To accomplish this, the wrap is provided with one or more engagement members that retain respective fingers of the surgeon""s hand, or other manipulator, with respect to the wrap. The engagement members enable ready release of the surgeon""s hand or other manipulator from the wrap, at a predetermined detachment time after it has been properly located relative to the heart""s affected region and secured in an appropriate orientation thereon. The engagement members essentially allow selected fingers of the treatment hand to act as direct clamps for the wrap while providing close tactile feedback as the surgeon feels the underlying heart.
In a preferred embodiment, the engagement members comprise loop members that encircle all or a substantial portion of the selected fingers. The loop members can be attached to the wrap so that the surgeon""s fingers engage respective loop members during wrap implantation, and can be withdrawn from the loop members after implantation is complete. Typically, the loop members are disposed about a circumference of the wrap at predetermined circumferential locations, near the distal end of the wrap so that the selected fingers can wrap around the patient""s heart to manipulate the wrap thereover. In one embodiment related to a wrap with opposing free ends, the loop members are arranged so that four fingers are engaged thereby, while the thumb remains free to hold opposing free ends of the wrap in place over the heart while the free ends are joined together in an overlapping relationship to achieve a desired circumference and angular shape with respect to the affected ventricle(s).
In an alternate embodiment, the loop members can be removeably attached to the wrap using hooks, pins or other suitable attachment mechanisms. After fixation of the wrap to the patient""s heart is completed, the loop members are themselves withdrawn by the surgeon. In another alternate embodiment, the removable loop members can comprise the ends of a special surgeon""s glove that selectively and removably engage locations on the wrap.
The wrap having engagement members according to this invention can be either a closed cup or tube having a predetermined circumference profile/geometry arranged to fit over the ventricular portion of the heart and be compressed into a final shape thereon. Alternatively, the wrap can be an open strip of material that is wrapped around the ventricular region of the heart and subsequently secured to it to thereby provide desired compression to the ventricular region.